This invention relates generally to devices for scattering dry lawn chemicals to lawn or yard areas, and more particularly to a detector which may he secured to such devices in order to confine application of such chemicals to a given area.
A typical broadcast or rotary type lawn spreader 10 is illustrated in FIG. 1 and includes a hopper section 12 and a support frame 14 for supporting the hopper section above the ground. As seen in FIG. 1, the support frame 14 comprises two wheels 16 and 18 coupled together by an axle 20. A first bevel gear 22 coupled to the axle and adapted to rotate therewith drivingly engages a second bevel gear 24 having a disk member 26 coupled thereto. Disk member 26 is disposed directly below one or more openings (not shown) in the base of hopper section 12 and is adapted to rotate in response to forward or reverse movement of the spreader. The surface of disk member 26 generally includes vertical projections 27 which contact the material and scatter it by centrifugal force. As will be readily ascertained, dry material placed in the hopper section is red by gravity onto the upper surface of disk member 26 as it rotates, thereby causing the material to be scattered over a wide area as the spreader is moved by the user.
In a spreader of the depicted in FIG. 1, the flow rate of material being fed from the hopper section and delivered to the surface of a lawn area is regulated by adjusting the size of the openings in the base of the hopper section. However, while the amount of material applied to a particular area can he controlled in this manner, it will be appreciated that the area of distribution over which the material is scattered can not. Thus, a primary disadvantage of spreaders this type is that there is no provision for controlling the area of distribution. Without such control, there is a substantial risk of misapplication at the junctions of lawn areas and paved areas (i.e., sidewalks, streets, parking lots, etc.). The risk of misapplication is especially acute in narrow areas such as between sidewalk and curb areas. It will be appreciated that any herbicides, insecticides, or fertilizers inadvertently distributed onto such paved areas may be washed into storm drains and eventually into streams and rivers where they may cause serious damage to fragile wetland ecosystems and public water supplies.
A device for confining the material scattered by a rotary spreader is proposed in U.S. Pat. No. 2,500,682 entitled ADJUSTABLE SHIELD and issued to G. O. Hoffstetter on Mar. 14, 1950. This device requires special mounting provisions in the form of complementary eyes which are mounted in spaced pairs on opposite sides of the hopper section and on two plates. Bolts inserted through the respective eyes secure the plates to corresponding sides of the hopper section in an angular orientation selected to confine the spreading of material to a predetermined area. Although the Hoffstetter device does permit the plates to be angularly reoriented, it is not easily retrofitted onto an existing spreader. Moreover, before a plate member can be reoriented to change the angle of inclination, the bolts in each eye must first be loosened and then retightened after a desired orientation has been found.
Accordingly, it is a principal object of the present invention to provide a deflecting guard which may be retroactively fitted to a variety of existing rotary or broadcast spreaders of various dimensions and which can be easily adjusted to confine the application of dry materials to a selected area, thereby avoiding the disadvantages of prior art shield devices.